Understand mechanisms by which T lymphocytes (CTL) specifically lyse allogenic and syngeneic target tumor cells (TC) in vitro, specifically by: isolation and characterization of a cell-free, functionally reactive component from CTL and study of its mode of action on the target cell; determination of the role of membrane lipid composition and microviscosity on CTL-TC interaction; analysis of the biochemistry and structure of CTL-TC contact regions and events leading to lysis; and evaluation of the possibility that the TC has an active role in the lytic process.